Automatic defroster and moisture control for mechanical refrigerators



May 18, 1937. A. s. VOLPlN AUTOMATIC DEFROSTEH AND MOISTURE CONTROL FORMECHANICAL REFRIGERATORS 2 Sheets-Sheet 1 Filed Sept. 26, 1932 May 18,1937. A. s. VOLPIN 2,031,123

AUTOMATIC DEFROSTER AND MOISTURE CONTROL FOR MECHANICAL REFRIGERATORSFiled Sept. 26, 1932 2 Sheets-She et 2 E snia Patented Ma 18, 1937UNITED STATES PATENT OFFICE AUTOMATIC DEFROSTER AND MOISTURE CONTROL FORMECHANICAL REFRIGER- ATORS The invention relates to an improvement inthe collection and disposal of the moisture accumulating inrefrigerators.

With the development of mechanical refrigeration, it has been found thatconsiderable moisture accumulates upon the refrigerating coils andnecessitates the defrosting of the coil at frequent intervals. Theaccumulation of frost upon the coiLnot only impairs the efficiency ofthe refrigerating unit, but causes undesirable odors to remain withinthe box, because of the deposits of frost, whereas if the accumulatingmoisture can be removed from the box as it accumulates, the efficiencyof the coil is increased and the undesirable odors are removedimmediately.

It is, therefore, one of the objects of this invention to provide ameans and method of removing the moisture from the refrigeratingchamber.

Another object of the invention is to provide a method of collecting themoisture from the incoming currents of air prior to the time when suchcurrents of air come in contact with the refrigerating coil.

Another object of the invention is to provide an automatic defrostingmechanism for use with and to control the operation of mechanicalrefrigerators.

Another object of the invention is to provide a mechanism which isarranged to make a contact with the currents of air circulating in the"refrigerating chamber so that the moisture will adhere to the mechanismand in this manner be segregated and withdrawn from the refrigeratingchamber.

Still another object of the invention is to provide a baffle plate inthe refrigerating chamber of mechanical refrigerators for the purpose ofcollecting moisture at temperature above freezing.

Still another object of the invention is to provide an automaticdefrosting mechanism for refrigerators wherebythe accumulation of apredetermined quantity of moisture will control the operation of thepower unit so that the refrigerating coil will be out off until the coilhas been defrosted, whereupon the power unit will be again out into thecircuit to continue its operation.

Still another object of the invention is to provide in combination amoisture accumulator and an automatic defrosting mechanism whereby themoisture will be continuously discharged from the refrigerator and thecoil will be automatically defrosted upon the discharge of apre-determined volume of moisture from the refrigerating chamber.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings wherein Figure 1 shows a diagrammatic view of oneform of the invention and embodies both the moisture collector and theautomatic defrosting mechanism.

Fig, 2 is a central vertical section of the control mechanism for theautomatic defrosting device.

Fig. 3 shows a front elevation of a refrigerator box which has beenequipped with one form of the present invention.

Fig. 4 is a section taken on the line 44 of Fig. 3 and shows a. sideelevation of the collector mechanism.

Fig. 5 shows a front view of a refrigerating box which has been equippedwith a combination I moisture collector and a defrosting device whichare adapted for use in conjunction with each other to obtain automaticcontrol of the moisture in the box.

Figs. 3, 4, and 5 show standard forms of refrigeration cabinets or boxeswhich are now in general use. It is usual in boxes in this type toprovide a power and compressor unit which is connected to therefrigerating coil or unit which is disposed within the refrigeratingchamber. In Fig. 3 the box is indicated generally at 2 and therefrigerating chamber at 3. The refrigerating coil 4 is disposed withinthe refrigerating chamber 3 in the usual manner.

Fig. 1 shows a diagrammatic arrangement of the mechanisms used inconnection with the box and the power unit is shown at 5. The compressor6 is operated from the power unit in any desired manner and compressesthe refrigerant which then passes to the refrigerator coil 6. The powerunit 5 is usually an electric motor which is controlled by a switch 1.This switch is usually wired into a power circuit, the lead Wires ofwhich are shown at 8 and 9. An auxiliary switch II] has been provided inthe Fig. 1 arrangement and this switch will be later described.

The coil 4 is usually made up of a plurality of pipes l2 through whichthe refrigerant is arranged to circulate, and connected to these pipesare the distributor or dissipating plates l3 which are to be cooled bythe coils. The air confined within the refrigerating chamber 3 comes incontact with these distributor or dissipating plates l3 in order to becooled and maintain the refrigerating chamber at the desiredtemperature.

It seems obvious that the cooling of the air in and about therefrigerating coil 4 causes the air to move downwardly by gravity aroundthe coil. This causes an indraft of air at the top of the coil.Obviously in the refrigerating chamber the colder air being of greaterspecific gravity settles to the bottom of the chamber, whereas thewarmer air rises to the top. When the door of the chamber is open andthere is an inrush of warm air, it immediately rises to the top of thechamber and follows the general flow of circulation in the chamber,which in the arrangement of the parts shown in Fig. 3 would be in acounterclockwise direction.

With the circulation of the air as just described, the warm air risingto the top of the box and passing downwardly over the coil is caused todeposit the moisture which it carries. This moisture condenses uponthepipes l2 and the distributor plates |3 of the coil to such an extentthat it interferes with the heat transfer of the refrigerating coil. Inorder to lessen the accumulation of this moisture in the form of frostupon the coil and its associated parts a collector pan or tray 20 hasbeen provided adjacent to the coil 4. In the Fig. 1 modification of theinvention this collector plate has been mounted upon the reservoir ortank 2| which is provided in connection with some forms of unit. If theunit is of the type which does not embody such a tank, the collectorplate 20 can then be mounted upon the refrigerator coils or spacedtherefrom in any suitable manner.

The supports 22 serve to space the collector plate from therefrigerating unit to such an extent that the temperature of thecollector plate will be normally above freezing. It-is intended thatthis collector plate 20 will be cooled to some extent and be maintainedat a temperature slightly higher than that of the refrigerating coil, sothat when the circulation of warm air approaches the refrigerating unitit will first come in contact with this collector plate. The moisture inthe air will be condensed upon the collector plate and in this mannerremoved from the air so that it will not be present at the time the airpasses over or through the refrigerating coil. The fact that this'mosture is condensed and accumulated at a temperature above freezingpermits it to flow by gravity and thus be removed from the chamber. Withthis function in view, the plate 20 has been formed with a more or lessconcave configuration, as indicated at 24, and is provided with grooves25 so that the moisture will drain to a dischgge pipe 26. The water isled by gravity through this pipe 26 to a cup or container 21, or thepipe 26 may lead out of the chamber as does the pipe 63 to be laterdescribed.

The container 21 forms a portion of a control mechanism to accomplishthe automatic defrosting of the box. This container is shown in sectionin Fig. 2 and may be designed of any size so that a pre-determinedamount of moisture can accumulate therein. The pipe 26 leads directly tothis container and it is intended that when a pre-determined amount ofmoisture collects in this container that a switch such as III will beoperated to cut off the power unit so that the coil will be defrosted.In order to accomplish the automatic operation of the switch It! a floatmember 30 has been provided in the container 21 and is intended to moveupon the surface of the accumulated body of water 3|. The container 21is provided with a needle valve 32 which normally closes the outlet pipe33 due to the weight of the needle valve. This valve is disposedconcentrically within the float 30 so that the float will slide withrespect to the valve and will not move the valve until the float hasraised to the elevation of the stop ring 34, which is positioned nearthe top of the valve. This stop ring 34 is so placed that when the float30 engages the stop ring the needle valve 32 will be raised and the bodyof moisture 3| may flow out of the pipe 33. In order to retain the valve32 open until all of the moisture has had an opportunity to escape, abar 35 is positioned on the yoke 40 and is arranged to engage the stopring 34 of the valve 32.

As the moisture escapes from the container 21, the float member 3!! willmove downwardly with the liquid; but the needle valve will be retainedin raised position by the switch mechanism Ill and the yoke 40 whichwill be later described. When, however, the defrosting operation hasbeen accomplished the switch mechanism I0 is moved to closed position bythe thermostat 56 to turn on the power unit, and when this switch movesto closed position the needle valve will be released to move downwardlyby gravity when the yoke 40 moves down. The lower stop 38 is positionedon the valve 32 and will be engaged by the bottom of the float as thefloat moves down; upon release of the needle valve the float will tendto move the valve to closed position.

When the valve 32 closes the discharge of liquid will be cut off and anew charge will then begin to accumulate. This completes a cycle of thefloat chamber and causes a periodic discharge from the chamber of theconstant accumulation of moisture from the collector plate 20.

In order that the power unit will be automatically controlled by thefloat 30, the yoke 40 has been provided which is separated from thefloat 30 and extends through the top of the container 21. This yoke isattached to the lever arm 4| which is a part of the bell crank lever 42.This bell crank lever is pivoted on the pin 43 and has two extendingarms 44 and 45, the pin 43 being carried by the housing It. The arm 44serves to support the lower end of the spring 46, the opposite end ofwhich is attached to the blade 41 and the knife switch 48. This blade 41is pivoted on the pin 43 and the spring 46 is under tension so that ittends to draw the blade 41 to either one side or the other of the centerline joining the pin 43 and the lower end of the arm 44. This is knownas a click switch, and will, therefore, snap the knife switch 48 intoeither closed or open position upon movement of the arm 4|. When the arm4| moves downwardly, or to the approximate position shown in Fig. 2, thelower end of the arm wardly. This moves the lower end of the arm.

44 to the left, as viewed in Fig. 2, and when this arm passes the center.under the pin 43, the spring 46 will snap the blade 48 to the left andout of the engagement with the contact 50. This snap of the lever due tothe spring 46 will also on the part of the housewife.

snap the yoke .40 upwardly so that the bar 35 will strike the stop 34and quickly raise the valve 32.

The wires 5| and 52 are connected to the electric circuit including thewires 8 and 9 of the switch 1. When the circuit is thus broken by theopening of the switch 48, the power unit is cut off and therefrigerating coil is thus no longer supplied with refrigerant. Thetemperature thereof gradually raises so that the frost which hasaccumulated on the coil will melt.

After the coils have been defrosted, it is, of course, desirable toagain close the electric circuit so that the temperature of the box willnot rise beyond a desirable degree. With this in mind, the finger hasbeen provided upon the bell crank lever 42 and this finger extends in aposition to be engaged by the rod 55. This rod is in turn connected to athermostat 56 which is mounted upon one of the distributor plates l3, orupon some other part of the refrigerator coil 4. When the temperature ofthe coil during defrosting rises to a degree wherein the frost will havemelted from the unit, the thermostat operatesto expand, and move the rodupwardly. This movement of the rod 55 may be effected by a sylphonelement which causes the end 5'! thereof to engage with the arm 45 tomove the arm up-' wardly. This movement tends to cause pivoting of thebell crank lever 42 so that the lower end of the arm 44 is moved to theright, as seen in Fig. 2, until the spring 46 moves over center andclicks the blade 48 into engagement with the contact 50. The closing ofthis switch 48 lowers the arm 4| and the yoke 40 connected thereto torelease the valve 32.

Thus we have the power unit cut off by the accumulation of moisture topermit defrosting and the power unit again turned on or cutinto thecircuit when the temperature of the refrigerating coil is raised to adegree sufficient to have permitted defrosting.

From the foregoing description it is apparent that the size of thecontainer 21 may be adjusted or varied at will, so that the defrostingof the refrigerator will occur when a pre-determined amount of moisturehas accumulated.

This period when automatic defrosting will take place is independent ofany time interval, but is dependent upon the accumulation of moisture.Thus if the box is opened frequently, or articles containing aconsiderable amount of moisture are deposited in the box, the box willautomatically defrost in a shorter period than if less moisture ispermitted to enter the box. a

With a refrigerator equipped with the foregoing mechanism, the housewifeis relieved of any worry whatever as to whether or not the refrigeratingunit requires defrosting. A certain percentage of the moisture iswithdrawn from the chamber before it accumulates as frost upon therefrigerating coil. The eiiiciency of the coil is, therefore, increased.The period when defrosting is required is lengthened and the coil isautomatically defrosted without further attention It is usual withrefrigerators to maintain a tray beneath the refrigerating coil and whenthe coil defrosts the water will accumulate within this tray.

Figs. 3 and 4 show another form of the invention for accumulating andremoving the moisture before such moisture is permitted to condense uponthe refrigerating coil. Fig. 3 shows the usual form of refrigeratingunit and crypt which is disposed at one side adjacent to the top of thebox. The circulation of air in the refrigerating chamber 3, aspreviously stated, would be counterclockwise, the warm air rising to thetop of the chamber and the cool air passing out at the base of therefrigerating coil. A collector or condenser plate has been provided inthe refrigerating chamber 3 and is indicated generally at 60. This platemay take any form desired. The present form, however, illustrates aplurality of fins or baffles 6|.

A plurality of these fins may be provided and they may be arranged inany desired configuration, preferably with a view to having the greatestamount of air come in contact therewith. The plate is to be eitherinsulated or spaced from the top or walls of the box so that thetemperature of the plate will be lower than that of the walls of the boxand may take other forms than here shown.

These fins or baffles will, of course, be cooler than the incoming airand the moisture of the air will condense upon the fins. Figure 4 showsthese fins as being tapered toward the rear of the refrigerating chamberso that the moisture condensing upon the fins will drain to the rear ofthe chamber and be received in the trough 62. It is to be understoodthat these baffles, being at the top of the refrigerating chamber willbe at a temperature above freezing so that the moisture will remain inliquid form and drain rapidly along the baffles and flow from the trough62 into a suitable discharge or outlet pipe 63. This pipe may leadeither to a container in the base of the refrigerator, or to anysuitable drain. It is believed that this method of accumulating andcol-* lecting the moisture before it reaches the refrigerating coil willaid materially in the refrigeration which can be obtained. Therefrigerating unit need operate over a lesser period because the heattransfer will be accomplished more readily, the amount of frostcondensing upon the coils will be greatly reduced and in some instancesit will be unnecessary to defrost the coil at all, whereas if the coilis maintained at a very low temperature, then occasional defrosting willbe necessary. The interval between defrosting periods, however, will bedouble or treble because of the great quantity of moisture which isremoved from the air by the collector baffles before the air reaches thecoil. If the air passing to the coil is dry air, then there will belittle or no condensation upon the coil and the defrosting will beaccomplished in a shorter time.

If the refrigerating chamber is of considerable size, or if for anyother reason it is desired to maintain the baffle plate 60 and the finsill at a cooler temperature than the top of the box, a suitableconnection may be made between the collector plate and the refrigeratingunit, so that the heat of the collector plate will be withdrawn by therefrigerating coil.

It is intended that the area of this connecting portion can be adjustedor varied with a view of maintaining the collector plate at the desiredtemperature, so that the moisture will condense thereon, but at such atemperature that the plate and fins will remain above the freezingpoint. With this in mind, the connecting flange 65 has been provided andis best seen in Figs. 3 and 4 as being connected to one end of therefrigerating coil and passing upwardly where it is connected with thebafile plate.

Fig. 5 shows a combination of the automatic defrosting mechanism of Fig.1, and the com- 7 with a view of obtaining automatic defrosting 21, sothat the automatic defrosting may be provided in combination with eitherthe collector tray 20, or the moisture accumulating plate 80. Or ifdesired, as shown in Fig. 5, both the collector tray and the collectorplates may be provided.

While the invention has been shown and described as embodying acollector tray and collector plates, it is to be distinctly understoodthat the invention contemplates a method as-well as a means of removingthe moisture from the refrigerating chamber, and that the invention isnot to be limited by the structure shown and described, but is to belimited only by the scope of the appended claims.

What I claim as new is:

1. A moisture collector for refrigerators including in combination withthe refrigerating coil a collector member adapted to be contacted by thecirculating air and to condense moisture from the air, means to drainoff the accumulating moisture, and additional means to cut of! thesource of power for the coil to cause defrosting upon the accumulationof a predetermined quantity of moisture.

2. A method of automatically defrosting refrigeration coils includingcondensing a portion of the moisture fromthe circulating air at atemperature above freezing and controlling the operation of therefrigerating coils upon condensation of a predetermined quantity ofmoisture to cause defrosting.

3. An automatic defrosting device for refrigerators including means toaccumulate a portion of the moisture which is condensed from thecirculating air at above freezing temperature, and means controlling theoperation of the refrigeratingunit, which means is operable to cut offthe operation of the unit and cause defrosting upon the accumulation ofa predetermined quantity of moisture in said first means.

4. In a refrigerating unit of the character described including amoisture collector, a float operable' by the accumulation of moisturefrom the said collector, and control means for the ref-rigerating unitoperable by said float to cut off the unit to cause defrosting thereof.

ALEXANDER S. VOLPIN.

